The scope of the invention is an electronic spirit level for measurement of inclination from 0 to 360 degrees and different placements of electrical resistance and conductors within the housing of the electronic level. It is purposed for general use in construction, engineering, households etc. and for special purposes, where high accuracy is required as in laboratories, military equipment etc.
Problem 1
Measurement of all inclination angles from 0 to 360 degrees should be possible.
Problem 2
In different domains of use a different measurement of inclination is required. What is needed are different types and forms of resistors and conductors, their different placements within the housing and different requirements to reduce the mistakes at measurement.
Known is the following Application of patent dealing and thus: Priority application SI, P-9900196, filed Aug. 13, 1999, and international application PCT/SI 00/ 00018, filed Jul. 26, 2000.
In a circular tube being bent into a round ring and only partially filled with electrically conducting liquid along the entire perimeter a resistor is placed in the form of a wire with an equally varying sectional area. Therefore the resistance of the system depends upon the position of the air bubble. The resistance is measured and calculated into angular degrees and displayed upon the screen. By that the housing can be more or less filled with liquid. On the outer side the coils can be placed tightly one beside the other, where each of the coils is separately connected to the measuring instrument. When the alternating electric voltage is connected upon the wire in the inside, electric voltage in all coils shall be induced. Where the air bubble is placed the induced voltage in the coils is also different. By successive measurements in all coils it can be precisely ascertained where at the moment the air bubble is situated. The air bubble and the inner wire can be substituted by a small metallic ball.
The measurement of inclination angle is performed with aid of an electronic instrument. Very accurate value is displayed upon the screen in form of digits. The solution is possible in nine manners.
1. The housing formed as a circular tube curved in a circular ring is partially filled with liquid. On the outer side of the housing electrically separated plates of capacitor are placed along the whole length of the round circle. Every capacitor is separately connected to the measuring instrument and placed on the exact angular degree. Because of the difference in relative dielectric constant between air and liquid it can be precisely ascertained, by successive measurements in all capacitors, where at the moment the air bubble is placed. The air bubble can be short or long and the housing can be formed as a circular ring or a circular cylindrical vessel.
2. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. Within the housing, resistance in the form of a wire is placed on the wall of the circular tube In the direction of the tube cross-section. The wire is in a form of one coil. The resistors are placed in defined angular degrees along the whole ring and are mutually electrically separated, having equal electric resistance. Each coil is separately connected to the measuring instrument. If all these resistors are connected to alternate or direct electric voltage, it is possible with consecutive measurement of resistance in all resistors to accurately determine in which resistors the current flows through the electrically conducting liquid and in which it flows through the resistors which are in the air in an air bubble. In this way it can be precisely ascertained where at the moment the air bubble is situated With interpolation of the beginning and the end of the air bubble calculation can be performed exactly, where there is the middle of the air bubble and with it the angle of inclination.
3. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. Within the housing, electrical contact in form of a wire is placed on the wall of the circular tube in the direction of the tube cross section. Electrical contact includes only a part of the circumference of the tube cross-section. The contacts are placed at determined angular degrees along the whole ring and are mutually electrically separated.xe2x80x94Every contact is separately connected to the measuring instrument Electrically conducting liquid can be connected with the source of electric energy with one or more contacts. All the contacts that are tied to the measuring instrument get connected on one pole, where as the electrically conducting spirit gets connected to the other pole. Over the wetted contacts in the electrically conducting liquid current flows over the contact which are in an air bubble or it does not. In this way it can be precisely ascertained where at the moment the air bubble is situated.
4. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. In the housing upon the walls of the tube along the whole circumference a resistor is placed in form of wire, wound in a spiral where the distance between each winding is uniformly increasing. In the entire spiral no two lengths between the windings are the same. The coils are placed in the direction of the tube cross-section. The initial coils are mutually electrically separated. Electric voltage is connected to the spiral and with corresponding instrument the actual resistance of this system can be measured. Through one part of its path the current is flowing through the electrically conducting liquid, but where an air bubble is located it is flowing only through the spiral. Because the number of windings is changing along the length, the resistance of the part of wire being within the air bubble depends upon the place where the air bubble is situated. The value of the entire system of resistance can be accurately measured and displayed upon the screen.
5. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. In the housing along its whole circumference a resistor is placed in form of a wire, wound in spiral, where the distance between each winding is uniformly increasing. In the entire spiral no two lengths between the windings are the same. The spiral is wound upon a round core, which is placed in the axle of the ring.
6. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. Within the housing, along the whole perimeter, resistance in the form of a metal strip is placed on the wall of the circular tube evenly changing its sectional area. The resistor is composed of two or several layers of wires being placed one upon another, so that there is contact between the flat surfaces, where the width is uniformly changing. The thickness of the wire is constant. The strips are mutually electrically separated, so that the flat surfaces in touch are insulated, but lateral edges along the whole thickness are not insulated. So it is enabled that all the layers being wetted are in direct contact with electrically conducting liquid. If on the wires electric voltage is connected the current flows a part of its path through electrically conducting liquid, but where there is an air bubble through each of the wire layers separately.
The housing as a circular tube, curved in a ring or cylindrical vessel is exactly half filled with electrically conducting liquid. There is a resistor within the housing, which is composed of 2 or more round metal strip. The thickness, therefore the cross-area of the wires remains constant. All the metal strips join into one point, which then serves as an electrical contact and is outside the housing. The strips are placed on the periphery of the housing, on the wall of the housing, parallel to each other, and mutually electrically separated. The resistor takes up only xc2xd of the circumference of the round ring and is divided into 2 or more segments. Each of the segments is separately connected to the voltage and a measuring instrument. If measuring angles which are smaller then 360 degrees the resistor can take up less then xc2xd of the circumference of the round ring. Small angles require only one segment.
7. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. In the housing on the wall of the tube, along the whole circumference a resistor is placed in the form of a wire, wound in spiral, where the distance between each winding is uniformly increasing. When the diameters of the wire are extremely small, for example smaller than 0.01 mm., because of the large number of coils of spiral the resistance is increasing. The measurement of such big values is difficult The spiral which includes the whole circumference of the ring is divided in two or several mutually separated segments. Each segment is separately connected to the measuring instrument, In this manner high resistance is divided into smaller values.
The housing as a circular tube, curved in round ring is exactly half filled with electrically conducting liquid. In the housing on the wall of the tube, along the whole circumference a resistor is placed in the form of a wire, wound in spiral, where the distance between each winding remains constants The distance between coils is the same. The spiral takes up only xc2xd of the circumference of the housing. It is divided into 2 or more segments, each of the segments is separately connected to the voltage and a measuring instrument If measuring angles smaller then 360 degrees the spiral can take up less then xc2xd of the circumference of the housing. For smaller angles only one segment is required.
8. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. The air bubble is short including only some angular degrees. In the housing upon the wall of the tube, along the whole circumference a resistor is placed in the form of a wire wound in spiral, where the distance between each winding is uniformly increasing . In the entire spiral no two lengths between the windings are the same. Between the first and the last coil of the resistor there is an electrically separated resistor which is placed upon the wall of the tube as well and can include one or several coils. Both resistors are separately connected to the measuring instrument. When the position of inclination is such that simultaneously the beginning and the end of the resistor are in the air bubble, the measured value of resistance belongs to entirely different inclinations.
The resistor which is placed between the first and the last coil, is also in the air bubble. Because the resistor is separately connected to the measuring instrument it can be precisely ascertained which measured resistance belongs to which inclination.
9. The housing as a circular tube, curved in a ring is partially filled with electrically conducting liquid. In the housing upon the wall of tube the electrical conductors are placed along whole circumference. They are composed of several layers of flat metal strip being put upon each other. The strips are mutually electrically separated so that the flat surfaces which are touching each other are insulated, but the edges are not The conductors are placed along the whole perimeter of the tube cross-section and are electrically separated. The conductors have equal sectional area along its whole length. The whole circle is covered with coils, being placed close one to the other or even partially covering each other. The coil is placed so that the axle of a coil is perpendicular to the tangent of the wire.
An advantage of all cited solutions is, besides of the accurate measurement and reading, not depending on the visual ability of the user in this that they enable the measurements of inclination from 0 to 360 degrees.
The accuracy of the measurement depends on the making of the housing, resistors respectively conductors and of the quality of the liquid. For accurate measurement the inside of the housing must be as smooth as possible. The resistors which are tightly adapted to the wall of the housing must be as thin as possible, so that they influence the smoothness of the surface less and that it enables as dense as possible winding of the spiral respectively with multi-layer resistors bigger change of resistance with the change of the cross-section. The liquid must be optimally electrically conductive, optimally viscous so that it can as good as possible glide along the housing and resistor and that it reacts well to the smallest change of inclination and that it has optimal capillary wetting ability diminished also when the air bubble in housing is under increased pressure. By some executions a thermal sensor is required, which is a connection to the measurement instrument. Measurement instrument considers the changes at measurement which are a consequence of thermal dilatation.